Shaft assembly



Oct. 26, 1965 c. w. FITZGERALD SHAFT ASSEMBLY Original Filed Sept. 20,1961 TNVENTORt CHARLES W. FITZGERALD BY ATTORNEY United States Patent O3,213,703 SHAFT ASSEIVRLY Charles W. Fitzgerald, Franklin, Pa., assignorto Joy Manufacturing Company, Pittsburgh, Pa., a corporation ofPennsylvania Continuation of application Ser. No. 139,475, Sept. 20,1961. This application (let. 15, 1964, Ser. No. 498,451

Claims.v (Cl. 74-432) This application is a continuation of myapplication Serial No. 139,475, led September 20, 1961, now abandoned.

This invention relates to a shaft assembly and more particularly to ashaft assembly having a plurality of spaced drive or driven membersmounted thereon with sealing devices mounted between adjacent members toprovide for proper lubrication of the assembly.

In prior shaft assemblies such as those having multiple sprockets it hasbeen the general practice to employ a plurality of internally splinedsprockets mounted on an externally splined shaft which rotatively,drivingly, supports the sprockets to cause orbital movement of a set ofchains trained about two complete sets of such sprockets, a set of drivesprockets and a set of idler sprockets, respectively. Such multiplesprocket sets are used for conveying and loading, however, thisinvention is particularly applicable to cutter chain -drive and idlersprocket sets as applied on a ripper type continuous miner such as thatshown and described in the U.S. Patent 2,908,374. It has further beenthe general practice to provide for suitable axial spacing of suchsprockets by the use of axially extended, internally splined, hubportions of such sprockets abuttingly engaged with similar hub portionsof the adjacent sprockets. Such sprocket sets have generally beenemployed with no provision for lubrication of the spline surfaces withinthe sprockets which are in abutting contact with the external spline ofthe shaft. Although such devices have served the purpose, they have notproved entirely satisfactory under all conditions of service for thereason that the splines wear out too rapidly to be consistent with theeconomical operation of the device.

It has been found that, because of the manufacturing operations andassembly techniques applied to such multisprocket devices, a significantamount of clearance must be maintained between the internal splines ofthe sprockets and the external splines of the shaft. Such clearanceobviously allows relative motion to take place between the internal andexternal splines during opera-tion of the device, which splines, beingunlubricated, are subject to rapid wear. Another difficulty associatedwith the aforesaid spline clearance arises from the fact that suchmultisprocket devices are often used in an atmosphere heavily loadedwith rock or coal dust, so that highly abrasive dust particles enterinto the aforementioned spline clearance and cause extremely rapidwearing of the splines.

A multiple sprocket device constructed in accordance with the presentinvention provides spacers between the sprockets which, together withseals between the sprockets and spacers, transform the aforementionedspline clearances, within the sprockets, into closed spaces continuousthroughout the length of the splined portion of the shaft. Such spacersare provided with lubrication fittings by which the closed spaces can befilled with lubricant to reduce the wear normally present between thesplined surfaces. Such sealing also effectively excludes abrasivematerial from the spline clearances and thus further reduces the rate ofwear of the spline surfaces.

It is therefore an object of this invention to provide a shaft assemblyhaving a multiplicity of sprockets in driving or driven relationshipwith a drive shaft on an idler shaft.

"'ice It is a further object of this invention to provide a shaftassembly having lubricant sealing means between individual sprockets ofa multiple sprocket apparatus.

It is a more specific object of this invention to provide a shaftassembly comprising spacers and seals between individual sprockets, of asprocket set, mounted on a splined shaft, whereby lubrication suppliedto the shaft through the spacers may be effectively retained upon theshaft and within the sprockets.

It is a further specific object of this invention to provide a shaftassembly having spacers and seals between the individual sprockets of amultiple sprocket apparatus wherein continuous spline clearance spacesformed between internal splines of the sprockets and external splines ora shaft, common to all lthe sprockets, will be effectively sealed fromthe surrounding atmosphere.

These and other objects and advantages of this invention will becomemore fully apparent upon consideration of the following description anddrawings, in which:

FIG. 1 is a fragmentary axial section through a shaft assembly havingmultiple sprockets constructed in accordance with the principles of thisinvention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary view of a portion of FIG. 1.

In FIG. 1 there is shown a shaft assembly 10, constructed in accordancewith the principles of this invention which assembly 10 comprises aplurality of externally toothed, internally splined, hub members orsprockets 12 mounted upon and drivingly associated with an elongatedexternally splined .generally cylindrical shaft 14. The sprockets 12 areaxially spaced apart by, and overlappingly engaged with, a plurality ofhollow cylindrical internally splined spacing members 16. The shaft 14is rotatably journaled in suitable anti-friction bearings 18 suitablyreceived in hollow cylindrical bearing carriers 20 rigidly secured inthe end portions of a suitable fork type mounting frame 22. It is to benoted that only one of the bearings 18, the bearing carriers 20, and theend portions 22, is shown because of the fragmentary nature of FIG. 1which omits these details from the left hand end of the drawing. Theshaft 14 is also provided with a main splined portion 15 extending froman unsplined portion forming a bearing seat near one end of the shaft 14to a similar unsplined portion near the other end. The main splinedportion 15 is suitably received by the internal splines of the sprockets12 and the spacers 16 with a necessary clearance space 38 produced bymaking the minor diameter of the internal splines greater than the minordiameter of the main splined portion 15 in the conventionalmanufacturing operation. It is to be appreciated that although aparticular number of splines, sixteen, is shown in the drawing of themain splined portion 15 any number of splines such as fourteen oreighteen or more or less can be used without departing from theprinciples of this invention, Rigidly secured to splined outer endportions of the shaft 14, and rotatable in splined relationshiptherewith, is a pair of suitable internally splined drive gears 24suitably driven by a suitable transmission (not shown) provided withpower from an electric motor or other source of mechanical energy.

Each sprocket 12 has two reduced diameter end portions 26, at axiallyopposite ends thereof, respectively, forming two annular shoulderportions 28, on oposite sides of the sprocket, which are abuttinglyengaged with the end surfaces of the spacer members 16. The reduceddiameter end portions 26 are overlappingly engaged with axialcounterbores 30 formed in both ends of each of the spacing members 16. Aperipheral groove 32 spaced axially inwardly from the end of eachreduced diameter end portion 26 is formed in each portion 26 andreceives a resilient circular sealing element 34, such as an O-ring,which is held in a compressed state in engagement with the peripheralgroove 32 and the axial counterbore 30. The element 34 provides a sealagainst lubricant leakage outwardly from the splines and air or waterleakage inwardly from the surrounding atmosphere. It is to be noted thateach pair of sprockets 12 is spaced apart but connected, in oil tightcommunication, by a spacing element 16 and a pair of sealing elements34. The outer end portion 26 of each of the outermost sprockets 12 issimilarly overlappingly engaged by an axial counterbore 30 of aninternally splined end spacing member 36, the inner end surface of whichis abuttingly engaged with the shoulder portion 28 of the outermostsprocket 12. The outer end of the end spacing member 36 is rotatablyreceived by the bearing carrier 20 and is provided with a labyrinth andoil seals in a conventional manner to retain gear oil furnished to theanti-friction bearing 18 from the transmission hereinbefore mentioned.

It is to be noted that the spacing elements 16 and 36 together with thesprockets 12 form a continuous, internally splined cover means 37,rotating as a unit with the shaft 14 and extending from one end to theother of the main splined portion of the shaft 14. Since the minordiameters of the internally splined sprockets 12 and spacing members 16and 36 are somewhat greater than the minor diameter of the externallysplined main splined portion 15 of the shaft 14, there is formed acontinuous space 38 extending from one end of the main splined portion15 to the other end thereof. Each of the spacers 16 and 36 is providedwith a conventional lube fitting 40 threadedly engaged in a threadedradial bore 41, to provide for introducing lubricant into the continuousspace 38 at axially spaced points along the periphery of the continuouscover means 37.

It is to be further noted that the internal splines in the spacingmembers 16 can be omitted with the advantage of reduced cost andincreased lubricant storage without departing from the lubricantretaining and air excluding principles of this invention. When thesplines are omitted each spacing member 16 will be provided with anaxial bore having a diameter substantially equal to the major diameterof the external splines 15.

It is to be appreciated that pressure applied to a lubricant by aconventional pressurized lube gun operatively Vattached to the lubefitting 40 will force the lubricant through the space 38 and into manyother spaces between the splines which communicate with the continuousspace 38 thus filling all available empty spaces within the continuouscovering 37 and obviating the possibility of abrasive substances orwater from the surrounding atmosphere being introduced into thesespaces.

The advantages inherent in the multiple sprocket apparatus 10 of thisinvention are the result of providing lubrication on the wear surfacesof the spline and the exclusion of abrasive substances and watertherefrom. These advantages include increased useful life of thesprockets and shaft, smoother operation for longer periods of timebecause original fit is maintained for a greater period of time, andconsequent reduced maintenance cost for the apparatus.

A preferred embodiment of this invention having been described, it is tobe realized that modifications thereof may be made without departingfrom the broad spirit and scope of this invention. Accordingly, it isrespectfully requested that this invention be interpreted as broadly aspossible and be limited only by the prior art.

What is claimed is:

1. A shaft assembly comprising, an elongated externally splined shaft, aplurality of internally splined hub members spaced longitudinally onsaid shaft for rotation therewith, internally splined spacer members onsaid shaft and rotatable therewith, said spacer members extendingaxially of said shaft between adjacent hub members respectively, andeach of said hub members having means thereon engageable with the saidspacer members adjacent thereto for providing a seal therebetween,respectively.

2. A shaft assembly as defined in claim 1 in which the minor diametersof the splines on said shaft are radially spaced from the minordiameters of the splines on all of said hub and spacer members and atleast one of said spacer members having means for lubricating saidshaft.

3. A shaft assembly comprising, an elongated externally splined shaft, aplurality of internally splined first members spaced longitudinally onsaid shaft for rotation therewith, each axially spaced end portion ofeach of said first members having an integral portion extending axiallyoutwardly therefrom, internally splined spacer members on said shaft androtatable therewith, said spacer members extending axially of said shaftbetween adjacent ones of said first members, with the opposite endsthereof located adjacent axially adjacent ones of said integralportions, respectively, and each of said integral portions having meansthereon to provide a seal between said each integral portion and the endof said spacer member adjacent thereto.

4. A shaft assembly as defined in claim 3 in which the minor diametersof the splines on said shaft are radially spaced from the minordiameters of the splines on all of said hub and spacer members and atleast one of said spacer members having means for lubricating saidshaft.

5. A machine comprising, a frame having spaced portions, an elongatedsplined shaft extending between said spaced portions and rotativelysupported thereby, a plurality of internally splined hub members spacedlongitudinally on said shaft for rotation therewith, internally splinedspacer members on said shaft and rotatable therewith, said spacermembers extending axially of said shaft between adjacent hub members,respectively, each of said hub members having means thereon engageablewith the said spacer members adjacent thereto for providing a sealtherebetween respectively and means carried by said shaft outwardlyadjacent the outermost ones of said hub members respectively whichcooperates with said spaced portions and said outermost hub members toprovide a seal between said means said spaced portions and saidoutermost hub members.

6. A shaft assembly comprising, an elongated externally splined shaft, aplurality of internally splined first members spaced lonigtudinally onsaid shaft for rotation therewith, each axially spaced end portion ofeach of said first members having an integral portion extending axiallyoutwardly therefrom, internally splined tubular spacer members on saidshaft and rotatable therewith, said spacer members extending axially ofsaid shaft between adjacent ones of said first members respectively withthe opposite ends thereof overlying axially adjacent ones of saidintegral portions, and means engaging said opposite ends of said spacermembers and said integral portions respectively to provide a sealtherebetween.

7. A shaft assembly as defined in claim 6 in which internally splinedsecond members are spaced on said shaft axially outwardly adjacent theoutermost ones of said irst members and means engaging said secondmembers and said outermost ones of said first members to provide a sealtherebetween.

8. A shaft assembly comprising, an elongated externally splined shaft, aplurality of internally splined hub members spaced longitudinally onsaid shaft for rotation therewith, tubular spacer members mounted onsaid shaft, said spacer members extending axially of said betweenadjacent hub members respectively, and each of said hub members havingmeans thereon engageable with the said spacer members adjacent theretofor providing a seal therebetween, respectively.

9. A shaft assembly comprising, an elongated externally splined shaft, aplurality of internally splined hub members spaced longitudinally onsaid shaft for rotation therewith, axially bored spacer membersextending axially of said shaft between adjacent hub membersrespectively, and each of said hub members having means thereonengageable with the said spacer members adjacent thereto for providing aseal therebetween respectively.

10. A shaft assembly as defined in claim 9 in which the minor diametersof the splines on said shaft are radially spaced from the minordiameters of the splines on al1 of said hub members and at least one ofsaid spacer members having means for lubricating said shaft.

No references cited.

DON A. WAITE, Primary Examiner.

1. A SHAFT ASSEMBLY COMPRISING, AN ELONGATED EXTERNALLY SPLINED SHAFT, APLURALITY OF INTERNALLY SPLINED HUB MEMBERS SPACED LONGITUDINALLY ONSAID SHAFT FOR ROTATION THEREWITH, INTERNALLY SPLINED SPACER MEMBERS ONSAID SHAFT AND ROTATABLE THEREWITH, SAID SPACER MEMBERS EXTENDINGAXIALLY OF SAID SHAFT BETWEEN ADJACENT HUB MEMBERS RESPECTIVELY, ANDEACH OF SAID HUB MEANS HAVING MEANS THEREON ENGAGEABLE WITH THE SAIDSPACER MEMBERS ADJACENT THERETO FOR PROVIDING A SEAL THEREBETWEEN,RESPECTIVELY.